The Hoffmann kiln is a series of batch process kilns. Hoffmann kilns are the most common kiln used in production of bricks and some other ceramic products. Patented by German Friedrich Hoffmann for brickmaking in 1858, it was later used for lime-burning, and was known as the Hoffmann continuous kiln.
A Hoffmann kiln consists of a main fire passage surrounded on each side by several small rooms. Each room contains a pallet of bricks. In the main fire passage there is a fire wagon, that holds a fire that burns continuously. Each room is fired for a specific time, until the bricks are vitrified properly, and thereafter the fire wagon is rolled to the next room to be fired.
Each room is connected to the next room by a passageway carrying hot gases from the fire. In this way, the hottest gases are directed into the room that is currently being fired. Then the gases pass into the adjacent room that is scheduled to be fired next. There the gases preheat the brick. As the gases pass through the kiln circuit, they gradually cool as they transfer heat to the brick as it is preheated and dried. This is essentially a counter-current heat exchanger, which makes for a very efficient use of heat and fuel. This efficiency is a principal advantage of the Hoffmann kiln, and is one of the reasons for its original development and continued use throughout history. [1] In addition to the inner opening to the fire passage, each room also has an outside door, through which recently fired brick is removed, and replaced with wet brick to be dried and then fired in the next firing cycle.
In a classic Hoffmann kiln, the fire may burn continuously for years, even decades; in Iran, there are kilns that are still active and have been working continuously for 35 years. Any fuel may be used in a Hoffmann kiln, including gasoline, natural gas, heavy petroleum and wood fuel. The dimensions of a typical Hoffmann kiln are completely variable, but in average about 5 m (height) x 15 m (width) x 150 m (length).
The Hoffmann kiln is used in almost every country.
In the British Isles there are only a few Hoffmann kilns remaining, some of which have been preserved. [2]
The only ones with a chimney are at Prestongrange Industrial Heritage Museum and Llanymynech Heritage Area. The site at Llanymynech, close to Oswestry was used for lime-burning and has recently been partially restored as part of an industrial archaeology conservation project supported by English Heritage and the Heritage Lottery Fund. [2]
Two examples in North Yorkshire, the Hoffmann lime-burning kiln at Meal Bank Quarry, Ingleton, and that at the former Craven and Murgatroyd lime works, Langcliffe, are scheduled ancient monuments. [3] [4]
There is an intact but abandoned Hoffmann kiln without a chimney present at Minera Limeworks; the site is abandoned but all entrances to the kiln have been grated-off, preventing access. The kiln is in a very poor state of repair, with trees growing out of the walls and the roof. Minera Quarry Trust hopes one day to develop the area into something of a tourist attraction. The Grade II listed Hoffmann brick kiln in Ilkeston, Derbyshire, is also badly neglected, although the recently installed fencing offers some protection for the building and for visitors. [5]
At Prestongrange Museum, outside Prestonpans in East Lothian, the Hoffman kiln is still standing and visitors can listen to more about it via a mobile phone tour. [6]
There is a nearly complete kiln in Horeb, Carmarthenshire. [6]
There is still a working kiln at Kings Dyke in Peterborough, which is the last site of the London Brick Company, owned by Forterra PLC.[ citation needed ]
In Victoria, Australia, at the Brunswick brickworks, there are two surviving kilns converted to residences, and a chimney from a third kiln; there is another in Box Hill, Victoria; also in Melbourne. [7]
In Adelaide, South Australia, the last remaining Hoffman kiln in the state is in at the old Hallett Brickworks site in Torrensville. [7] [8] [9]
There is one at St Peters in Sydney, New South Wales. [7]
In Western Australia, the kiln at the Maylands Brickworks in the Perth suburb of Bayswater, which operated from 1927 to 1982 is the only remaining Hoffman kiln in the state. [10]
There is a complete kiln in the restored Tsalapatas brick Factory in Volos Greece that has been converted to an industrial museum. [12]
There are two in New Zealand.[ citation needed ]
Kaohsiung city in Taiwan is also home to a Hoffman kiln, built by the Japanese government in 1899. [13] [ circular reference ]
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A lime kiln is a kiln used for the calcination of limestone (calcium carbonate) to produce the form of lime called quicklime (calcium oxide). The chemical equation for this reaction is
The Don Valley Brick Works is a former quarry and industrial site located in the Don River Valley in Toronto, Ontario, Canada. The Don Valley Brick Works operated for nearly 100 years and provided bricks used to construct many well-known Toronto landmarks, such as Casa Loma, Osgoode Hall, Massey Hall, and the Ontario Legislature. Since the closure of the original factory, the quarry has been converted into a city park which includes a series of naturalized ponds, while the buildings have been restored and opened as an environmentally focused community and cultural centre by Evergreen, a national charity dedicated to restoring nature in urban environments.
Llanymynech is a village straddling the border between Montgomeryshire/Powys, Wales, and Shropshire, England, about 9 miles (14 km) north of the Welsh town of Welshpool. The name is Welsh for "Church of the Monks". The village is on the banks of the River Vyrnwy, and the Montgomery Canal passes through it.
The Yarralumla brickworks, also known as the Commonwealth Brickworks, was one of the earliest construction projects in Canberra, Australia. It was built in the suburb of Yarralumla to produce the bricks used to build many of Canberra's early buildings. It opened in around 1913 and operated until its closure in 1976. It is known for producing the bricks used to build itself.
A brickworks, also known as a brick factory, is a factory for the manufacturing of bricks, from clay or shale. Usually a brickworks is located on a clay bedrock, often with a quarry for clay on site. In earlier times bricks were made at brickfields, which would be returned to agricultural use after the clay layer was exhausted.
The Minera Limeworks were extensive lime quarries and kilns at Minera in Wrexham, Wales. It was located at grid reference SJ253520, near the villages of Gwynfryn, Minera, and Coedpoeth and was locally referred to as The Calch.
Torrensville is a western suburb 3 km (1.9 mi) west of the centre of Adelaide, South Australia. It was named after Irish-born economist and chairman of the South Australian Colonisation Commission, Robert Torrens.
Prestongrange Museum is an industrial heritage museum at Prestongrange between Musselburgh and Prestonpans on the B1348 on the East Lothian coast, Scotland. Founded as the original site of the National Mining Museum, its operation reverted to East Lothian Council Museum Service in 1992.
J. Hallett and Son, founded in 1904, was for most of the 20th century South Australia's most important brickmaking firm. Founded by Job H. Hallett in 1889, his son Thomas Hallett became a partner in 1904. There were several sites across Adelaide's western suburbs, with Halletts retaining their identity until the 1960s, when the company was absorbed by the Nubrik Hallett group.
Llanymynech railway station was an important junction station on the Cambrian Railways mainline from Welshpool, Powys to Oswestry, Shropshire, serving the village of Llanymynech which is partly situated in Shropshire, England and partly in Powys, Wales.
Harpur Hill Quarry is a disused limestone quarry on Harpur Hill, Derbyshire, England. Limestone was extracted there from 1835 to 1952 for lime burning at lime kilns to produce quicklime. The quarry was used by the Royal Air Force as a chemical weapons storage depot during the Second World War, the largest such depot in the United Kingdom. Afterwards a number of captured German chemical munitions were disposed of at the site by burning, which was only partially successful. The RAF depot closed in 1960 and the site is now vacant.
Llanymynech Heritage Area is an historic former lime kiln, quarry and industrial site near the village of Llanymynech, Shropshire in the Welsh Marches. The site is adjacent to the A483 road and close to the Montgomery Canal. It is about 6 miles (10 km) south of Oswestry on the English side of the border, and about 9 miles (14 km) north of the Powys town of Welshpool.
The Brunswick Brick Tile & Pottery Company was established in 1870 on a 12-acre paddock on Albert Street Brunswick, as one of the first modern mechanical brickworks in Australia. It was also known as the Hoffman Patent Brick & Tile Company, Hoffman Brickworks, or just ' Hoffman's' for most of its 100 plus years of operation.
The Clackline Refractory, also known as Clackline Clay and Brick, is a heritage listed brickworks site in Clackline, Western Australia.
Newmarket Brickworks Chimney is a heritage-listed brickworks at 117 Mina Parade, Alderley, City of Brisbane, Queensland, Australia. It was built in 1912. It is also known as Hoffman Stack. It was added to the Queensland Heritage Register on 24 March 2000.
Pindi Pindi Brickworks is a heritage-listed former brickworks off the Bruce Highway, Pindi Pindi, Mackay Region, Queensland, Australia. It was built in 1933. It is also known as Evans Firebricks Ltd and Pindi Pindi Firebricks Company. It was added to the Queensland Heritage Register on 27 October 2000.
Llanymynech and Pant is a civil parish in Shropshire, England. It contains 23 listed buildings that are recorded in the National Heritage List for England. All the listed buildings are designated at Grade II, the lowest of the three grades, which is applied to "buildings of national importance and special interest". The parish contains the villages of Llanymynech and Pant, and the surrounding area. The border between England and Wales passes through Llanymynech, and this is marked by a boundary stone which is listed. The area was once important for the manufacture of lime, and seven groups of lime kilns are listed, together with the much larger Hoffmann Kiln and its chimney. In Llanymynech is a listed pair of houses, a public house, and a church together with a pair of gate piers, and a memorial in the churchyard. Elsewhere, the listed buildings include farmhouses, farm buildings, an ice house, a gin wheel, a former mill, and a canal bridge.
The Lithgow Valley Colliery and Pottery Site is a heritage-listed former pottery and colliery and now pottery and visitor attraction at Bent Street, Lithgow, City of Lithgow, New South Wales, Australia. It was built from 1876 to 1945. It is also known as Lithgow Pottery and Brickworks. The property is privately owned. It was added to the New South Wales State Heritage Register on 2 April 1999.
September 2008: Published online with revised contact details: Department for Environment and Heritage 2008
